A robust themnosensory response in natural environments requires an animal to integrate circuits for temperature detection with circuits for other sensory modalities. The circuits for all sensory modalities must also work robustly over a range of temperatures. C elegans offers an excellent opportunity to prot)e the molecular and cellular mechanisms that regulate circuit function across different temperatures as well as mechanisms that integrate thermosensory and non-thermosensory inputs. The use of novel quantitative behavioral assays, optical neurophysiology and the rich neurogenetics available in C elegans allows us to identify and characterize the molecular, neuronal and circuit determinants of thermal robustness and multisensory integration during navigational behavior. Here, we propose to probe the interplay between thermosensory and chemosensory navigational behaviors in C elegans. The principal thermosensory neurons (AFD), NaCI-sensing neurons (ASE), and olfactory neurons for chemoattractants (AWC) are presynaptic to the same interneurons (AIY). Thus, mechanisms for multisensory integration between thermosensory and chemosensory inputs may be located in the first synapse, and moreover, the thermosensory circuit, may play a direct role in temperature-dependent regulation of the chemosensory circuit. Our proposed multifaceted analyses will uncover novel mechanisms of thermal robustness and multisensory integration, principles of which are likely to be highly conserved.